Brake mechanism for trailers



Aug..9,1938. G. vA-LERY ETAL R 2 26 62] BRAKE MECHANISM FOR TRAILERS Filed April 29, 1937 i ,m i g; 4?

INVENTOR Q1158 27/ w ORNEY Patented Aug. 9, 1938 UNITED STATES PATENT OFFICE Application April 29, 1937, Serial No. 139,635

2 Claims.

This invention relates to an improvement in brakes for automotive trailers and has for its object the provision of a hydraulic brake mechanism for the trailer which will detachably connect into the car brake system and be synchronized therewith whereby the application of the brake on the car will simultaneously apply the brakes on the trailer.

A further object of the invention is the provision of a brake mechanism of the character described wherein a speedy coupling and uncoupling of the trailer brake mechanism with that of the towing car is had to thereby enable the trailer to be coupled and uncoupled in an expeditious manner without requiring time consuming operations necessary to disconnect the trailer brake system from that of the car.

Another object of the invention is to provide a trailer brake system arranged for coupling with that on the car and wherein the trailer brake system does not in any manner minimize the eifectiveness of the ,car brake system both when the trailer is coupled to and uncoupled from the car.

More particularly, the invention contemplates .the provision of a trailer brake mechanism includinga cylinder containing a fluid-actuating piston, said cylinder and piston arranged for detachable connection to a similar piston and cylinder on the towing car, the latter piston being moved by actuation of the car brake pedal, said piston in turn moving the piston of the trailer brake mechanism to cause the same to apply the trailer brakes when the car brakes are being applied.

These and other objects are accomplished by the invention, a more particular description of which appears hereafter and is pointed out in the claims appended hereto.

In the accompanying drawing forming a part hereof, Fig. 1 is a diagrammatic view of a car and attached trailer, showing the manner in which the car brake system and the trailer brake system are coupled together; Fig. 2 is a sectional view through the coupling member or cylinders; Fig. 3 is a sectional view on the line 3-3 of Fig. 2, looking in the direction of the arrows; Fig. .4 is a front view of the clamping member which conmeets the two parts of the cylinder shown in Fig. 2, together; Fig. 5 is a side elevation, with parts in section, of the portion of the cylinder which is attached to the trailer, disconnected from that portion which is attached to the car, and provided with means for maintaining the brakes of the trailer in position of application while the trailer is uncoupled from the car; and Fig. 6 shows the portion of the cylinder that is located on the car closed by a dust cap.

In Fig. 1 of the drawing, an automobile or towing car is indicated at I; the same having the conventional four wheels indicated at 8, the wheels being provided with the usual hydraulic brakes, connected-by the system of tubing 9 to the so-called master cylinder III which is in turn connected to the foot pedal II in the known manner. All of the elements thus far described are in general use on most motor cars manufactured at the present time.

Mounted at the rear end of the car and preferably at a convenient position on the chassis, is a part of the coupling member l2 in the form of 'a cylinder, said cylinder being connected into the system of tubing 9 by the tube It and. thereby forming part of the brake mechanism of the car. The trailer is diagrammatically indicated at l3 and is coupled to the car by the usual pivotal coupling IS. The trailer brake mechanism in cludes cylindrical coupling member I 6 of the same general shape as the cylinder l2 and arranged to be connected to the end of the same in the manner indicated in Fig. 2 when the trailer is coupled to the car. Cylinder It connects by flexible tubing I! to the tubes l8 which extend to hydraulic brakes of conventional construction provided on the wheels I!) of the trailer, said brakes being more or less similar to those employed on the car.

When the trailer is coupled to the car, the front end of cylinder l6 connects to the rear end of cylinder I2 in the manner indicated in Fig. 2.

For joining the two cylinders together in the manner indicated, the clamp shown in Figs. 3 and 4 or a similar connection may be employed. Said clamp comprises a plurality of segments 20, 2| and 22 pivotally connected together at the points 23.- The end of segment 20 is provided with a pair of lugs between which one end of a locking lever 25 is pivoted at 24. The end of the segment 22 is provided with similar lugs 26 between which the end of an adjustable link member 22 is pivoted at 28, said link having its opposite end pivoted at 29 between the sides of an elongated slot or aperture 30 formed in the locking lever 25. The knurled nut 3| enables the length of link 28 to be adjusted to enable the clamp to close to the extent required to cause the two cylinders l2 and Hi to be held securely end to end. To cause the clamp to draw the ends of the cylinders l6 and I2 toward one another and hold them tightly together, each of the cylinders is provided near its end with a circumferential rib 32, said ribs each having an inclined face 33, said faces on the ribs being engaged by similar inclined faces on the inside of clamp segments 2|, 2| and 22 so that when the clamp segments are brought together in closed podtion, as shown in Fig. 3, the inclined surfaces 33 on the ribs will be engaged by the complementary surfaces on the inside of the clamp segments and a cam action exerted to draw theends of cylinders l2 and I6 toward one another in close contact. To ensure a tight fit between cylinder portions i2 and I, the end of cylinder i2 is provided with a gasket 24 against which the end of cylinder i6 abuts when cylinders i2 and ii are placed together in cooperative relationship as shown in Fl 2.

in Fig. 4 the clamp is shown in its open position. To close it, the locking lever II is swung upward (as viewed in Fig. 4) this action drawing segment 22 and segment 22 together to cause the ends of the same to meet. The end of segment 20 is provided with an eye 35 similar to an eye 36 formed on the end of segment 22. When the two segments 25 and 22 are brought together, the

eyes 35 and 36 are aligned and a suitable locking pin may be inserted, if desired, through the aligned eyes. Then locking lever 5| is swun downwardly into locked position as shown in Fig. 3, this action causing link 28 and its lugs 26 to extend into slot 30 in the locking lever. The locking lever 25 is provided with an aperture 31 through which a lug 34 formed on segment 23 projects when the lever is in its closed position. Lug 38 is formed with a hole 3! near its free end for the reception of a lock, which when inserted through the hole 3!, will hold the clamp in its locked position. Through the clamp described, cylinder it may be instantlly coupled with cylinder II or as speedily uncoupled when required. Thus, when the trailer II is uncoupled from the car, the connection of the trailer braking system with the car brake system is one which can be almost instantly disconnected.

Cylinder I2 is provided with a lining member .40 as is customary in brake cylinders of this character, and mounted for reciprocation within lining member 40 is a piston 4! which is normally spring-pressed toward the right, as viewed in Fig. 2, by the coil spring 42. An adjustable stop 42 secured in the end oftpe cylinder l2 limits the movement of the piston toward the right under pressure of the spring 42. The opposite end of the cylinder I2 is closed by a plug 44 and the piston 4| is provided with a centrally located push-rod 45 which projects through plug 44 and extends into cylinder i6 and bears against a piston 46 movable in said cylinder. A coil spring 41 has one end resting against a seat 42 formed on piston 46 and has its other end bearing against a disk 5|! formed with anaperture 49 normally closed by a valve 5|, normally held in closed position by coil spring 52 surrounding the valve stem 53. The disk 54 and valve 5! are mounted over the chamber 54 formed in the end of cylinder Ii, which communicates with the tubing I! leading to the brakes on the trailer. Mounted on thetrailer is a supply tank or reservoir 55 containing hydraulic brake fluid, said tank connecting to cylinder it by means of the flexible tubing 58, said tubing leading into a passage 51 formed in the wall of cylinder It, said passage communieating with the interior of cylinder It by means of the spaced lateral passages 58 and 59. The

movement oi piston 45 toward the right, as

viewed in Fig. 2, is limited by means of a stop member 54 held in position by a snap ring".

The cylinder I5 is provided with several aligning pins, one of which is shown at 52 in Fig. 2. When the cylinder it is secured to the end of the cylinder l2 by means of the clamping member previously described, one of the aligning pins 62 enters into a bushing 53 threaded into the wall of cylinder l2 and contacts with the end of a stem or rod 54, movable in a passage 55. Said rod is normally forced toward the left as viewed in Fig. 2, by means of a coil spring 56 and when cylinder I5 is clamped against the end of cylinder I 2, the aligning pin 62 contacts against the end of rod 84 and forces said rod toward the right against the tension of spring 55. The end of rod 64 when thus forced by pressure of pin 52, contacts with a ball or check valve 51 located in the end of the cylinder l2 in the passage 26 where the tube connects to said cylinder. A bleeder plug 88 is located in a portion of said passage. Thus, while cylinder I6 is clamped on the end of cylinder i2, valve 61 is always held open so that fluid from the car braking system may enter cylinder i2. When the cylinder I6 is disconnected from cylinder i2, ball valve 51 is closed against its seat 68 and the supply of fluid from the braking system of the car into cylinder I2 is disconnected. When however, cylinder i6 is attached to the end of cylinder l2 the pin 62 contacting with rod 64 ,will open ball valve 51 permitting the brake fluidit'o enter throughtube l4 into cylinder l2 and thereby exert pressure against the end of piston 4| in a manner to be explained.

From the foregoing, the operation of the improved braking system will be readily understood. When the trailer is uncoupled or disconnected from the car, cylinder I6 is disconnected from cylinder l2 and the end of cylinder I2 is then closed by a dust cap 10 shown in Fig. 6. Said dust cap III is held in position on the end of cyl inder I 2 by means of the clamp shown in Fig. 4.

At this time, rod 64 is held away from the ball valve 61 by pressure of spring 65 and ball valve 61 is accordingly closed against seat 55 so that communication between cylinder l2 and the rest of the automobile braking system is shut oil permitting the braking system of the car to operate in the conventional manner.

When the trailer is coupledto the car, cylinder I6 is clamped against the end of cylinder l2, shown in Fig. 2. At this time the aligning pin exerts pressure on the end of rod 84, causing said rod .to open ball valve 61 and establish communication between cylinder I2 and the braking system of the car so that brake fluid may enter cylinder l2. Now, when the foot pedal ll of the car is pressed, fluid will be forced through tube l4 into the end portion of cylinder l2 and against the end of piston 4| in said cylinder. The pressure of the braking fluid against piston 4i will cause said piston to be thrust to the left in Fig. 2 and its push rod 45 will similarly thrust piston 46 in cylinder ii in the same direction. Cylinder It contains braking fluid supplied from reservoir or tank 55, and when piston 45 is thrust to the left by pressure of rod .45, the pressure of fluid against the inner end of valve 5| will cause said valve to open 'so that the fluid will be forced through chamber 54 into tube l1 and accordingly through the tubes ll leading to the brakes on the wheels I! of the trailer. Upon release of pressure on the foot pedal Ii, springs 41 and 42 will force the respective pistons 46 and 4i back to their former positions.

' head It, and surrounded by the spring 84.

the brakes of the trailer in an applied position when the trailer is parked, and is disconnected from the car. There is shown a closure cap 15 provided near its periphery-with hook-shaped members 16 which are clamped over the rib 32 on cylinder I6 by tightening up the wing nuts I! mounted on the hooks l6. Said member 15 is formed with a central opening I8 which receives a threaded rod 18. on the other end of which is mounted a cap 80 and within which a sleeve 8! is contained. Mounted within said sleeve is a plunger 82 terminating in a rounded The outer end of threaded rod 19 receives an operating handle 95 pivoted at 86 to the end of rod 19.

By means of handle 85 the rod I9 may be threaded inwardlyor retracted, such movement causing the spring-pressed plunger 82 to bear with more or less resilient force upon the end of piston 46 to thereby force said piston toward the left, as viewed in Fig. 2. and cause the same to force the brake fluid through tubes I1 and I 8 to the brakes on trailer wheels It, to thereby apply the brakes. A locking nut 81 may be adjusted to the proper position on threaded rod 19 to hold the brakes in locked position. By loosening the wing nuts TI on hook 16, the cap 15 and partscarried thereby can be quickly removed when it is desired to couple up the, trailer and its brake system with the car and the cylinder I! carried thereby.

From the foregoing, it will be obvious that the structure may be modified in many particulars without departing from the spirit of the invention. with the structure described, a very effective and safe braking system is provided wherein an application of both the brakes on the car and on the trailer is had simultaneously, yet the trailer maybe speedily uncoupled from the car without in any way disturbing the brakingsystem thereon.

What we claim is:

1. An apparatus of the character described comprising, anautomotive trailer provided with fluid-operated brakes, a fluid-containing cylinder carried by the trailer, a piston therein for forcing fluid to the brakes, a cylinder carried by the car, said car cylinder having a piston and means connected thereto for causing the piston in the car cylinder to move the piston in the trailer cylinder, a valve for controlling the flow of fluid into the car-cylinder, means for automatically holding said valve in closed position while the car cylinder is not connected to the trailer cylinder, and means carried by the trailer cylinder the flow of braking fluid into said cylinder, spring 7 means for normally holding said valve closed while said cylinder is uncoupled from the other cylinder, andmeans carried by the last mentioned cylinder for opening said valve against 

